diff --git a/packages/web/server/lib/opencode/settings-helpers.js b/packages/web/server/lib/opencode/settings-helpers.js
index 9e0baff0..68b7aa85 100644
--- a/packages/web/server/lib/opencode/settings-helpers.js
+++ b/packages/web/server/lib/opencode/settings-helpers.js
@@ -616,6 +616,9 @@ export const createSettingsHelpers = (dependencies) => {
     if (typeof candidate.terminalFontSize === 'number' && Number.isFinite(candidate.terminalFontSize)) {
       result.terminalFontSize = Math.max(9, Math.min(52, Math.round(candidate.terminalFontSize)));
     }
+    if (typeof candidate.editorFontSize === 'number' && Number.isFinite(candidate.editorFontSize)) {
+      result.editorFontSize = Math.max(9, Math.min(32, Math.round(candidate.editorFontSize)));
+    }
     if (typeof candidate.terminalShell === 'string') {
       const shell = candidate.terminalShell.trim().toLowerCase();
       if (TERMINAL_SHELL_VALUES.has(shell)) result.terminalShell = shell;
diff --git a/packages/web/server/lib/opencode/settings-helpers.test.js b/packages/web/server/lib/opencode/settings-helpers.test.js
index 5c44cedf..a58f9a6e 100644
--- a/packages/web/server/lib/opencode/settings-helpers.test.js
+++ b/packages/web/server/lib/opencode/settings-helpers.test.js
@@ -104,6 +104,16 @@ describe('settings helpers', () => {
     expect(helpers.sanitizeSettingsUpdate({ collapsibleUserMessages: 'true' })).toEqual({});
   });
 
+  it('sanitizes and returns the persisted editor font size', () => {
+    const helpers = createTestHelpers();
+
+    expect(helpers.sanitizeSettingsUpdate({ editorFontSize: 20.6 })).toEqual({ editorFontSize: 21 });
+    expect(helpers.sanitizeSettingsUpdate({ editorFontSize: 8 })).toEqual({ editorFontSize: 9 });
+    expect(helpers.sanitizeSettingsUpdate({ editorFontSize: 33 })).toEqual({ editorFontSize: 32 });
+    expect(helpers.sanitizeSettingsUpdate({ editorFontSize: Number.NaN })).toEqual({});
+    expect(helpers.formatSettingsResponse({ editorFontSize: 20 })).toMatchObject({ editorFontSize: 20 });
+  });
+
   it('accepts messageStreamTransport as a persisted shared setting', () => {
     const helpers = createTestHelpers();